All publications herein are incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
The host response to biomaterials is an enormous challenge for the design of medical devices. This response is characterized by the infiltration of inflammatory cells and their chronic activation, and often leads to the formation of a fibrous capsule. The capsule functions to isolate the foreign body from the host immune system, but is also detrimental to many devices including surgical devices, cardiovascular or orthopedic implants, engineered tissue constructs, and implanted biosensors. The dense, collagen-rich tissue may occlude blood vessels, or prevent diffusion of small molecules and nutrients to and from the implanted device. While current efforts to reduce the immune response to biomaterials have focused on passivating the surface to prevent adhesion of proteins and inflammatory cells, these approaches have not been sufficient in eliminating the foreign body response. Alternatively, materials have been impregnated with anti-inflammatory or anti-proliferative pharmacological agents (for example, in drug-eluting stents), but this strategy ultimately prevents healing around the device. Thus, there is a need in the art for novel and effective design of implantable devices.